According to the elementtree spec, elements with no children test as false. We…

According to the elementtree spec, elements with no children test as false. We only want to skip checking for module ids if the module is actually not found

djangoapps/courseware/views.py

@@ -202,7 +202,7 @@ def index(request, course=None, chapter="Using the System", section="Hints"):
         module = etree.XML(etree.tostring(module_wrapper[0])) # Copy the element out of the tree
 
     module_ids = []
-    if module:
+    if module is not None:
         module_ids = module.xpath("//@id", 
                                   course=course, chapter=chapter, section=section)